pest. The Elegant Parser

• pest.rs
• pest.docs.rs
• pest.book

pest is a general purpose parser written in Rust with a focus on accessibility , correctness , and performance . It uses parsing expression grammars (or PEG) as input, which are similar in spirit to regular expressions, but which offer the enhanced expressivity needed to parse complex languages.

pest 是一个用 Rust 编写的通用解析器，重点关注可访问性、正确性和性能。它使用解析表达式语法（或 PEG）作为输入，其本质上与正则表达式类似，但提供了解析复杂语言所需的增强表达能力。

alpha = { 'a'..'z' | 'A'..'Z' }
digit = { '0'..'9' }

ident = { (alpha | digit)+ }

ident_list = _{ !digit ~ ident ~ (" " ~ ident)+ }
          // ^
          // ident_list rule is silent (produces no tokens or error reports)

int main() {
    return 5;
}

- FuncDecl
  - int_t: "int "
  - Identifier: "main"
  - FormalParams: ""
  - Block > Stmt > Return > Expr > Integer: "5"